Welding transformer



u y 29, 1952 A. SCHUTTLER 2,605,376

WELDING TRANSFORMER Filed Aug. 51, 1949 mmwmm II!" I fatented July 29,

- UNITED STATES PATENT OFFICE I I I i 2,605,376 a o I I WELDING TRANSFORMER Artur Schuttler, solingen-ohligs, Germany} as- Signor to Kronprinz Alrtieng'e's'ells'cha'ft fur 'Metallin'du'strie, Solingen-Ohligs, Germany A'pnlication August 31, 1949, Serial No. new In'Germany November 5, 1948 19 Claims.

' My present invention relates to a; weldingtrans- "former, and more particularly to arotating welding: transformer, particularly for pipe weldin machines, the secondary of which comprises? rotatablysupported hollow body which has two concentrical parts arrangedone inside the other andserving as carriers for the electrode discs.

More particularly my invention relates to a rotating welding transformer in which the outer hollow part is arranged on the outside'of onewall of the hollow body and'the inner part is arranged on the inside 'of'the other Wall of thehollow body.

"It is an object of my present invention to avoid joints in "the hollow body which are flowed through by acurre'nt. g

It is another object of my present invention to provide for an easy and simple exchange of the primary windings. I n

It isa further-object of my present invention to provide an'efiective cooling system of the transformer by air onthe inside and outside of the hollow body. g I K M It is known to provide rotating welding trans"- formers with a hollow body having supporting axles consisting of two or morepartswhich are cle ta'chably connected with one another by mechanical means. For instance, a'hollow body designed as a round casing 'closedon all sides and enclosingan angular iron core carryingthe'primarywindings is subdivided transversally to its axis ofrotati'on so that one half thereof maybe taken off like a lid. This subdivision being'necessary partlyfor reasons of manufacture, partly for the introduction of the iron core and the primary windings, has 'mostdetrimental effects from anelectrical point of 'view. The secondary current flows across the" subdividing joint through thehollow body, therefore necessitating a good electrical connection between the parts of the body. However, the making of a good electrical contact at the subdivided joint'is extremely dilifi cult. It requires not only special means for firmly 'pres'sing together the halves of the hollow body, but even at the best design of the subdividing joint, a high resistance of "transition remains so that .a heavy development of heat is caused at this spot; The consequence thereofis an--iindesirable high heating of the transformer. Furthermore, the parts of the hollow body can fuse at the subdividing joints. 7

A further disadvantage isthat the occasionally necessary exchange of the' primary windings is cumbrous and takes up much time because of the necessary removal of one half of the hollow body, all'the more since the bearingrof the rotatable hollow body 'hasto be removedonone side.

frne present invent nf avoids 'thse'drawbacks. and-comprises inits b'roadestaspecta secondary including a body;ajournal ;and an axle arranged concentrically to andinsidethe journal; the hollow'body, the journal, and the axleybein'g indirect connection, of material, 7 I With the' eX iressi n ei in d rect c n e'q ln' "o mat r l l it to be 7 understoodthat' the *partsfiniquestion either made inone piece or consistfofsveral se arate pieces which are "joined by welding for soldering so thatfinelectrical respect tlie'ybev ke' n pie q 7, i

Preferably, two discs are rigidly and"; 3.. res ect v oi hei wrn e theia xle so thatthe'discs-canact aswe'lding' ct o e .l c, s o .t i' lre ed. emb d ent .1, W presentfinvention; an; iron coreand a primary arranged onsaid core I are; enclosed byt'l re secoiikifafy, the hollow b odypffwhi'ch has preferably an open nd I015 n d si 1 d e ify- P femmmfi e. e v iv be as e, sha e 11 a t ula S on o b a t al y rect n lar cross section having broad"andsrnallw alls} and the journal is arranged on the outs ide f one'of th ad l v hereas th la st r s the inner isle of the opposite broadfwall; land-"protrud'e s through'thejournal. [The iron'surro 'ds part'of h esndi ro'r d'with d 'able yoke. lnone embodiment ofitheinven on thecore islrectangular, and two legs onwhich two straight coils forming the *primai'yfare ar- PlT iiab r 1 W l e s e r la n? ntionis 'prov'idedf vvith accolise h o surr undin hollow body and idedivvith nians'fondirefct; ing a flow o'fcofoling air through the'hOQ sub;- sta'ntially at right angles to the axis of rotation 6f the ho l wbed i ia m th b 'ldwfb is provided was notm the; wens and ribsarranged on the outside of the walls so that the cooling air' fiows overlthefribs and thfo ugh' the slotsinto the'int'erior-of the hollow body. It will be understood that the inventionav oid's thefca'use; for an undesirable product not heat.

ondary 'beingjsesigpeda one bqdy thgll bili'bDlfe e, introd ingsl F urtherir or*the primaries can b n d, eszst igh 991 s. whi h ar rr d the straight" legsof the iron corel Thecoolin'g Fig. 1 is a perspective view of a welding transformer according to my present invention, the electrode discs being omitted and some parts being broken away; and

Fig, 2 is a longitudinal section of the transformer shown in Figure 1, the electrode discs and the article to be welded being shown as well.

The welding transformer shown in the drawing is provided with a hollow body I, 2, 3, forming the secondary of the transformer and enclosing the primary I3 of the transformer and an iron core I4, I5 carrying the primary, The hollow body is made in one piece and open at two opposite sides thereof. Preferably it has the shape of a tubular section having a substantially rectangular cross section. The broad wall I of the hollow body is provided with a hollow journal 5, whereas the broad wall 2 of the hollow body is provided with an axle 4 concentrically arranged to said journal 5. The axle 4 and the journal 5 are running in ball or roller bearings 8 and I, respectively, the outer faces of which are supported by a stationary member (not shown). The journal 5 surrounds at a certain distance an axle 8 which is connected to and forms one piece with the inner side of the broad wall 2, and passes through the journal 5 and protrudes slightly from the same.

The hollow body I-3, the journal 5, and the axles 4 and 8 consist of one piece. Therefore, all the walls of the hollow body, the journal and the axles are in a direct connection of material with one another.

The journal 5 and the axle 8 are separated by a cylindrical gap and insulated against each other by a cylindrical sleeve -9 consisting of insulating material and arranged in 'the'gap. The journal 5 and the axle 8 carry, respectively, two circular electrode discs I and I I. The disc I!) is attached to the end of the journal 5, and the disc I I to the end of the axle 8. Both discs are secured to their supporting members in well known manner so that a good electrically conductive connection exists between the discs and the supporting members, respectively. The discs are separated by an air gap I2 and at their circumference provided with contact rings I2 which form together a semicircular recess corresponding to the shape of the pipe I6 the longitudinal seam of which is to be welded. The pipe I6 rests on two rollers I6.

The rimary windings of the transformer are arranged in the form of two substantially square straight coils I3 on the legs I4 of an iron core I4, I designed as a substantially rectangular frame surrounding the portion of the axle 8 which is situated inside the hollow body I3.

The core is made of transformer sheets which are tightly joined and pressed against one another at the ends of the frame. The two yokes I5 are detachably connected to the legs I4 so that one or the other yoke can be removed. After the removal of one yoke the iron core together with the two coils I3 is introduced into the hollow body [-3 through one of the side openings and 4 then the removed yoke is replaced in position. If it is intended to exchange the primaries, only one yoke has to be removed whereupon the core and the coils may be withdrawn from the hollow body.

The electric current is supplied to the coils I3 in well known manner by slip rings and sliding contacts (not shown). The current flowing in the coils I3 induces in the hollow body I3 a secondary current. The current passes through the wall of the hollow body, the axle 8, the electrode disc II, the pipe I6, the electrode disc III, the journal 5, and back through the walls of the rollow body as indicated in Fig. 2 by the arrow.

It will be seen that in the new design of the welding transformer no joint flowed through by a current is present in the hollow body forming the secondary of the transformer, Furthermore, an exchange of the primary windings is easy and simple to perform. Also, the transformer can be effectively cooled by air at its outside and inside.

The cooling of the transformer is effected in the following manner: The transformer is surrounded by a hood II which has the shape of a tube with an oblong cross section. One end of the hood I! is open whereas the other end is provided with a connecting piece I8 serving for connecting a fan to the hood I'I. Thus, a flow of cooling air can be made to pass through the hood at right angles to the axis of rotation of the transformer. This air stream flows not only along the outside of the hollow body, but also through its interior, thereby directly contacting the primary and the iron core. In order to enable the air stream to flow along these parts not only in the shown and similar angular positions of the transformer in which the hollow body I3 has its openings in the direction of the air flow, but also in other angular positions, the hollow body is provided with a plurality of slots I9 for the access of the cooling air. The slots I9 extend in the direction of the perimeter of the hollow body over its smaller walls 3, and the parts of the broad walls I and 2 adjoining thereto. The slots effect an increase in the cooled surface. In order to increase the latter still more cooling ribs 20 are provided in addition to the slots I9.

, In the embodiment shown in the drawing, the cooling ribs are arranged on the two smaller walls 3 of the hollow body, and run in the direction of the perimeter of the hollow body and are, therefore, in the angular position of the transformer shown in the drawing and in similar positions at right angles to the direction of flow of the air. Thus the ribs narrow the space between the smaller walls 3 of the transformer and the hood I! so that the air is compelled partly to flow through the interior of the hollow body. If the transformer has an angular position substantially turned through with respect to that shown in the drawing, the cooling ribs 28 are substantially parallel to the flow of the cooling air and are effectively cooled. In order to enable the coolin air to flow between the primaries and the iron core an air gap 23 surrounding the core practically from all sides is provided, except for the insulating rods 2I arranged at the corners of the cross section of the iron core I4 for carrying the windings of the coils I3.

Theoperation of this device is as follows: The article to be welded, for instance a pipe I6, is brought into position as shown in Figure 2. The current is then switched in and the transformer produces a welding current in the manner more fully described heretofore. At the same time,

51' thehollowbody with the partsconnected thereto is rotated, for instance by a belt (notshown),

running over the axle 4 The pipe 16- is'movedforward-by the rotation of the electro'de'discs l and H which may be assisted, if desired, by .a motion ofthe pipe of its own; Thus, it willbe seen that a seamin the pipe will be welded under the influence of the heat developed by the electric current in the seam of 'the pipe;

The hollow body l3" is preferablyimade, for

instance cast, in such manner that the journal 5 and the axle 8 form at first a common "axle. The latter is then provided'with a cylindrical gap serving to accommodatethe insulating sleeve 9 bymeans of a cylindrical bit or thelike, sub-' dividing the full axletinto thejourna'l Sand the axles surroun'ded'by it.

Various. modifications and changes can be made without leaving the scope-of the present invention. The iron l4; l5 may consist of a horseshoe-shaped body of metal sheets provided only with one yoke removably secured thereto. The cooling ribs may be arrangedat right angles to the direction of the perimeter of the walls of the hollow body so that they are-permanently parallel to the direction of the air flow. The axle 4 which is not flowed through by the current can be designed, if desired, as a part separate from the hollow body I--3, and connected by a screw connection with the hollow body. The ends of the broad walls I and 2 of the hollow body may be circular instead of being straight. In any case the hollow body and the iron core l4, l5 carrying the coils i3 are preferably so dimensioned and designed that'the edges thereof which are farthest away from the axis of rotation and also the outer edges of the cooling ribsarc situated on a circle 22 concentric to the axis ofrotation, the circle 22 being indicated by dottedlines in Figure 1. The hollow body I-3, the journal 5 and the axle 8 may consist of two or more pieces which are welded together and thus'in direct connection'of material. lihe transformer may havean iron'core with three legsand disc-like coils arranged in slots of the hollow body..

It will be understood that each of theelements described above, or two or more together, may also find'a useful application in other types of weldingtransformers, differing from the types described above.

While I have illustrated and described the invention as embodied in welding transformers particularly forpip'e welding machines, I do not intend to be limited to the details shown, since various modifications and structural changes may be made Without departing in any way from the spirit of my invention.

Without further analysis; the foregoing will so fully reveal the gistof my invention that others can by applying current knowledge readily adapt it for various applications without omitting features; that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, suclradaptations should and are intended to be comprehended within'the meaning and range of equivalence of the following claims.

What I claim as new and desire" to secure by Letters Patent is:

l. A rotatable welding transformer comprising in combination, an iron core; a primary ar-' rangedon said core; a'secondary enclosing said primary and at least part of said 'core'; said secondary including a hollow bodyhaving-at least one peri n'anently open endror introducing said core' and said'prima'ry into said 'hollow'bcdy; a ournal, and anaxle 'arranged concentrically to" andinside said 'journal; said'hollow body,- said journal, and said axlebeing in *directconnection of material.

2. A- rotatable weldingtransformer comprising in combination, an iron core; a primary arranged .on said core; a secondary enclosing said primary and at least part of said core; said secondary-including a hollow body having at least one permanently open end-for introducing said'core and said primaryinto' said hollow body, a-journal, and an axle arrangedconcentrically to and inside said-journal; said hollow body, said journal, and saidaxle being direct connection of material; and tw'o discs rigidly and conductively connected,

respectively, to said journal and said axle;' said discs acting as" welding electrodes.

3. A rotatable welding transformer comprising in combination, an iron core; a'primary' arranged on said core; asecondary enclosing said primary and at least part of said core; saidv secondary including ahollow body having at least one permanently open end for introducing a said core and said primary into said hollow'body, a journal, and an axle arranged concentrically to and insidesaid journal; said hollow body, said journal, and said, axle consisting-of one-piece.

4. A rotatable weldingtransformer comprising in combination, an iron core; a primary arranged on said core; asecondary enclosing said primary and at least part of said core, said secondary including a hollow body having the shape of a tubular section of substantially rectangular cross section having. broad and small walls; said hollow body having permanently open ends for introducing said iron core and said primary into said hollow body; a hollow journal arranged at the outside of one of said broad walls of said body; and an axle arranged concentrically to said journal on the inner side ofthe other broadf wall of said body and protruding through sa'idjournal; said hollow body, said journal, andsaid axle being in direct connection of material.

5. A rotatable welding transformer comprising in combination, a hollow body forming part of the secondary of the transformer'and having the shape of a tubular section of substantially rectangular cross'sectionhaving broad and small walls; said hollow body having permanently open ends; a hollow journal arranged at the outside of one of said broad walls of said body; an axle arranged concentrically to said journal on the inner side of the other broad wall of said body and protruding'through said journal; said hollow body, said journal, and said axle being in direct connection of material; a frame-shaped iron core surrounding part of said axle; a detachable yoke forming part of said core; and a primary arranged on saidcore, whereby said core and said primary can be brought into and out of position through any of said open ends of said hollow body.

6. A rotatable welding transformer comprising in combination, a hollow body formingpart of the secondary of the transformer and having the shape of a tubular section of substantially rectangular cross section having broad and small walls; said hollow body having permanently open ends; a hollow journal arranged at the outside of one ofsaid broad walls of said body; .an' axle arranged concentrically to said journal onthe inner side of theother broadwall of saidbodyand protruding through said journal; said hollow body, said journal, and said axle being in direct connection of material; a rectangular iron core surrounding part of said axle and having two legs; a detachable yoke forming part of said core; and two straight coils arranged, respectively, on said legs of said core, whereby said core and said primary can be brought into and out of position through any of said open ends of said hollow body.

7. A rotatable welding transformer comprising in combination, a hollow body having walls; a journal; an axle arranged concentrically to and inside said journal; said hollow body, said journal, and said axle being in direct connection of material and forming a secondary of the transformer; and cooling ribs arranged on the outside of said walls. I

8. A rotatable welding transformer comprising in combination, a hollow body having walls; a journal; an axle arranged concentrically to and inside said journal; said hollow body, said journal, and said axle being in direct connection of material and forming a secondary of the transformer; slots in said walls for the access of cooling air; and cooling ribs arranged on the outside of said walls.

9. A rotatable welding transformer comprising in combination, a hollow body having the shape of a tubular section of substantially rectangular cross section having broad and small walls; said hollow body having open ends; a hollow journal arranged at the outside of one of said broad walls of said body; an axle arranged concentrically to said journal on the inner side of the other broad wall of said body and protruding through said journal; said hollow body, said journal, and said axle being in direct connection of material; slots in said small walls and part of said broad walls; and cooling ribs arranged on the outside of small walls.

10. A rotatable welding transformer comprising a secondary including a hollow body, a journal, and an axle arranged concentrically to and inside said journal; said hollow body, said journal, and said axle bein in direct connection of material; a hood surrounding said hollow body; and means for directin a flow of cooling air through said hood substantially at right angles to the axis of rotation of said hollow body.

11. A rotatable weldirig transformer comprising a secondary including a hollow body, a journal, and an axle arranged concentrically to and inside said journal; said hollow body, said journal, .and said axle being in direct connection of material; said hollow body having two openings arranged at opposite ends of said body; a hood surrounding said hollow body; and means for directing a flow of cooling air through said hood and substantially at right angles to the axis of rotation of said hollow body.

12. A rotatable welding transformer comprising in combination, a hollow body having the shape of a tubular section of substantially rectangular cross section having broad and small walls; said hollow body having open ends; a hollow journal arranged at the outside of one of said broad walls of said body; an axle arranged concentrically to said journal on the inner side of the other broad wall of said body and protruding through said journal; said hollow body, said journal, and said axle being in direct connection of material, slots in said small walls and part of said broad walls;

cooling ribs arranged on the outside of said small walls; a hood surrounding said hollow body; and

8 means for directing a flow of cooling air through said hood substantially at right angles to the axis of rotation of said hollow body.

13. A rotatable welding transformer comprising in combination, a hollow body having the shape of a tubular section of substantially rectangular cross section having broad and small walls; said hollow body having open ends; a hollow journal arranged at the outside of one of said broad walls of said body; an axle arranged concentrically to said journal on the inner side of the other broad wall of said body and protruding through said journal; said hollow body, said journal, and said axle being in direct connection of material; slots in said small walls and part of said broad walls; cooling ribs arranged on the outside of said small walls; said slots and said ribs being arranged in the direction of the perimeter of said hollow body; a hood surrounding said hollow body; and means for directing a flow of cooling air through said hood substantially at right angles to the axis of rotation of said hollow body.

14. A rotatable welding transformer comprising in combination, an iron core; a primary arranged on said core; a secondary enclosing said primary and at least part of said core, said secondary including a hollow body having at least one permanently open end for introducing said core and said primary into said hollow body; a journal; an axle arranged concentrically to and inside said journal, said hollow body, said journal, and said axle being in direct connection of material; and cooling means associated with the walls of said hollow body.

15. A rotatable welding transformer comprising in combination, a hollow body forming part of the secondary of the transformer and having the shape of a tubular section of substantially rectangular cross section having broad and small walls, said hollow body having permanently open ends; a hollow journal arranged at the outside of one of said broad walls of said body; an axle arranged concentrically to said journal on the inner side of the other broad wall of said body and protruding through said journal, said hollow body, said journal, and said axle being in direct connection of material; a rectangular iron core surrounding part of said axle and having two legs; a detachable yoke forming part of said core; two straight coils arranged, respectively, on said legs of said core, whereby said core and said primary can be brought into and out of position through any of said open ends of said hollow body; and cooling means associated with at least the small walls of said hollow body.

16. A rotatable welding transformer comprising in combination, an iron core, a primary arranged on said core; a secondary enclosing said primary and at least part of said core, said secondary including a hollow body having first and second wall portions arranged oppositely to each other and consisting of one piece, said hollow body having at least one permanently open end for introducing said core and said primary into said hollow body; a first welding disc rigidly connected to said first wall portion of said hollow body, said first welding disc being provided with an aperture; an axle arranged concentrically to said aperture of said first welding disc and being in direct connection of material with said second wall portion of said hollow body; and a second welding disc rigidly connected to said axle and arranged parallel to said first welding disc.

17. A rotatable welding transformer comprising in combination, an iron core, a primary arranged on said core; a secondary enclosing said primary and at least part of said core, said secondary including a hollow body having first and second wall portions arranged oppositely to each other and consisting of one piece, said hollow body having at least one permanently open end for introducing said core and said primary into said hollow body, said first wall portion being provided with an aperture; a first welding disc rigidly connected to said first wall portion, said first welding disc being provided with an aperture concentric to said aperture of said first wall portion; an axle arranged concentrically to said apertures of said first wall portion and said first welding disc and being in direct connection of material with said second wall portion of said hollow body; and a second welding disc rigidly connected to said axle and arranged parallel to said first welding disc.

18. A rotatable welding transformer comprising in combination, an iron core, a primary arranged on said core; a secondary enclosing said primary and at least part of said core, said secondary including a hollow body having first and second wall portions arranged oppositely to each other and consisting of one piece said hollow body having at least one permanently open end for introducing said core and said primary into said hollow body; a first welding disc rigidly connected to said first wall portion of, said hollow body, said first welding disc being provided with an aperture; an axle arranged concentrically to said aperture of said first welding disc and consisting of one piece with said second wall portion of said hollow body; and a second welding disc rigidly connected to said axle and arranged parallel to said first welding disc.

19. A rotatable welding transformer comprising in combination, an iron core, a primary arranged on said core; a secondary enclosing said primary and at least part of said core, said secondary including a. hollow body having first and second wall portions arranged oppositely to each other and consisting of one piece, said hollow body having at least one permanently open end for introducing said core and said primary into said hollow body, said first wall portion being provided with an aperture; a first welding disc rigidly connected to said first wall portion, said first welding disc being provided with an aperture concentric to said aperture of said first wall portion; an axle arranged concentrically to said apertures of said first wall portion and said first welding disc and consisting of one piece with said second wall portion of said hollow body; and a second welding disc rigidly connected to said axle and arranged parallel to said first welding disc.

ARTUR SCHU'I'ILER.

REFERENCES CITED The following references are of record in the file of this patent:

' UNITED STATES PATENTS Number Name Date 2,156,692 Hixon May 2, 1939 2,241,015 Hunter May 6, 1941 2,370,485 Nichols Feb. 27, 1945 2,477,607 Hung-ate Aug. 2, 1949 2,561,739 Hunter July 24, 1951 FOREIGN PATENTS Number Country Date 265,411 Italy June 13, 1929 

